1
|
Wang J, Han S, Ye J. Topological regulation of a transmembrane protein by luminal-to-cytosolic retrotranslocation of glycosylated sequence. Cell Rep 2023; 42:112311. [PMID: 36972171 PMCID: PMC10520219 DOI: 10.1016/j.celrep.2023.112311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/02/2023] [Accepted: 03/11/2023] [Indexed: 03/28/2023] Open
Abstract
Transmembrane proteins must adopt proper topology to perform their functions. We previously demonstrated that ceramide regulates TM4SF20 (transmembrane 4 L6 family 20) by altering the topology of the transmembrane protein, but the underlying mechanism remains obscure. Here we report that TM4SF20 is synthesized in the endoplasmic reticulum (ER) with a cytosolic C terminus and a luminal loop before the last transmembrane helix where N132, N148, and N163 are glycosylated. In the absence of ceramide, the sequence surrounding glycosylated N163 but not N132 is retrotranslocated from lumen to cytosol independent of ER-associated degradation. Accompanying this retrotranslocation, the C terminus of the protein is relocated from cytosol to lumen. Ceramide delays the retrotranslocation process, causing accumulation of the protein that is originally synthesized. Our findings suggest that N-linked glycans, although synthesized in the lumens, may be exposed to cytosol through retrotranslocation, a reaction that may play a crucial role in topological regulation of transmembrane proteins.
Collapse
Affiliation(s)
- Jingcheng Wang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sungwon Han
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jin Ye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
2
|
Kim BM, Lotter‐Stark HCT, Rybicki EP, Chikwamba RK, Palmer KE. Characterization of the hypersensitive response-like cell death phenomenon induced by targeting antiviral lectin griffithsin to the secretory pathway. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1811-1821. [PMID: 29509998 PMCID: PMC6131415 DOI: 10.1111/pbi.12917] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 02/24/2018] [Accepted: 02/28/2018] [Indexed: 05/23/2023]
Abstract
Griffithsin (GRFT) is an antiviral lectin, originally derived from a red alga, which is currently being investigated as a topical microbicide to prevent transmission of human immunodeficiency virus (HIV). Targeting GRFT to the apoplast for production in Nicotiana benthamiana resulted in necrotic symptoms associated with a hypersensitive response (HR)-like cell death, accompanied by H2 O2 generation and increased PR1 expression. Mannose-binding lectins surfactant protein D (SP-D), cyanovirin-N (CV-N) and human mannose-binding lectin (hMBL) also induce salicylic acid (SA)-dependent HR-like cell death in N. benthamiana, and this effect is mediated by the lectin's glycan binding activity. We found that secreted GRFT interacts with an endogenous glycoprotein, α-xylosidase (XYL1), which is involved in cell wall organization. The necrotic effect could be mitigated by overexpression of Arabidopsis XYL1, and by co-expression of SA-degrading enzyme NahG, providing strategies for enhancing expression of oligomannose-binding lectins in plants.
Collapse
Affiliation(s)
- Bo Min Kim
- Center for Predictive MedicineJames Graham Brown Cancer CenterDepartment of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | | | - Edward P. Rybicki
- Department of Molecular & Cell BiologyInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Rachel K. Chikwamba
- BiosciencesCouncil for Scientific and Industrial Research (CSIR)PretoriaSouth Africa
| | - Kenneth E. Palmer
- Center for Predictive MedicineJames Graham Brown Cancer CenterDepartment of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| |
Collapse
|
3
|
Yamasaki LH, Arcuri HA, Jardim ACG, Bittar C, de Carvalho-Mello IMV, Rahal P. New insights regarding HCV-NS5A structure/function and indication of genotypic differences. Virol J 2012; 9:14. [PMID: 22239820 PMCID: PMC3271958 DOI: 10.1186/1743-422x-9-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 01/12/2012] [Indexed: 12/25/2022] Open
Abstract
Background HCV is prevalent throughout the world. It is a major cause of chronic liver disease. There is no effective vaccine and the most common therapy, based on Peginterferon, has a success rate of ~50%. The mechanisms underlying viral resistance have not been elucidated but it has been suggested that both host and virus contribute to therapy outcome. Non-structural 5A (NS5A) protein, a critical virus component, is involved in cellular and viral processes. Methods The present study analyzed structural and functional features of 345 sequences of HCV-NS5A genotypes 1 or 3, using in silico tools. Results There was residue type composition and secondary structure differences between the genotypes. In addition, second structural variance were statistical different for each response group in genotype 3. A motif search indicated conserved glycosylation, phosphorylation and myristoylation sites that could be important in structural stabilization and function. Furthermore, a highly conserved integrin ligation site was identified, and could be linked to nuclear forms of NS5A. ProtFun indicated NS5A to have diverse enzymatic and nonenzymatic activities, participating in a great range of cell functions, with statistical difference between genotypes. Conclusion This study presents new insights into the HCV-NS5A. It is the first study that using bioinformatics tools, suggests differences between genotypes and response to therapy that can be related to NS5A protein features. Therefore, it emphasizes the importance of using bioinformatics tools in viral studies. Data acquired herein will aid in clarifying the structure/function of this protein and in the development of antiviral agents.
Collapse
Affiliation(s)
- Lilian Ht Yamasaki
- Department of Biology, Sao Paulo State University--UNESP, Sao Jose do Rio Preto, SP, Brazil.
| | | | | | | | | | | |
Collapse
|
4
|
Novel Concepts About the Role of Lectins in the Plant Cell. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 705:271-94. [DOI: 10.1007/978-1-4419-7877-6_13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
5
|
Zielinska DF, Gnad F, Wiśniewski JR, Mann M. Precision mapping of an in vivo N-glycoproteome reveals rigid topological and sequence constraints. Cell 2010; 141:897-907. [PMID: 20510933 DOI: 10.1016/j.cell.2010.04.012] [Citation(s) in RCA: 691] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 02/08/2010] [Accepted: 04/07/2010] [Indexed: 01/09/2023]
Abstract
N-linked glycosylation is a biologically important protein modification, but only a small fraction of modification sites have been mapped. We developed a "filter aided sample preparation" (FASP)-based method in which glycopeptides are enriched by binding to lectins on the top of a filter and mapped 6367 N-glycosylation sites on 2352 proteins in four mouse tissues and blood plasma using high-accuracy mass spectrometry. We found 74% of known mouse N-glycosites and discovered an additional 5753 sites on a diverse range of proteins. Sites almost always have the N-!P-[S|T]-!P (where !P is not proline) and rarely the N-X-C motif or nonconsensus sequences. Combining the FASP approach with analysis of subcellular glycosite localization reveals that the sites always orient toward the extracellular space or toward the lumen of ER, Golgi, lysosome, or peroxisome. The N-glycoproteome contains a plethora of modification sites on factors important in development, organ-specific functions, and disease.
Collapse
Affiliation(s)
- Dorota F Zielinska
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, Martinsried D-82152, Germany
| | | | | | | |
Collapse
|
6
|
Miura Y, Sakurai Y, Hayakawa M, Shimada Y, Zempel H, Sato Y, Hisanaga SI, Endo T. Translocation of Lysosomal Cathepsin D Caused by Oxidative Stress or Proteasome Inhibition in Primary Cultured Neurons and Astrocytes. Biol Pharm Bull 2010; 33:22-8. [DOI: 10.1248/bpb.33.22] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yuri Miura
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
| | - Yoko Sakurai
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
| | - Masato Hayakawa
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
- Department of Biological Sciences, Tokyo Metropolitan University
| | - Yukiko Shimada
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
| | - Hans Zempel
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
| | - Yuji Sato
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
| | | | - Tamao Endo
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology
| |
Collapse
|
7
|
Mlcochová P, Barinka C, Tykvart J, Sácha P, Konvalinka J. Prostate-specific membrane antigen and its truncated form PSM'. Prostate 2009; 69:471-9. [PMID: 19107881 DOI: 10.1002/pros.20894] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Prostate specific membrane antigen (PSMA) is a type II transmembrane protein overexpressed in prostate cancer as well as in the neovasculature of several non-prostatic solid tumors. In addition to full-length PSMA, several splice variants exist in prostatic tissue. Notably, the N-terminally truncated PSMA variant, termed PSM', is prevalent in healthy prostate, and the ratio of PSMA/PSM' mRNA has been shown to correlate with cancer progression. The widely accepted hypothesis is that the PSM' protein is a translation product arising from the alternatively spliced PSM' mRNA. METHODS Differential ultracentrifugation, cell surface biotinylation, Western blotting, and enzyme activity measurement were used to study the origin and localization of the PSMA/PSM' variants in prostatic (LNCaP; lymph-node carcinoma of the prostate) and non-prostatic (HEK293) cell lines. These experiments were further complemented by analysis of the N-glycosylation patterns of the PSMA/PSM' proteins and by site-directed mutagenesis. RESULTS We identified PSM' protein expression in both the LNCaP cell line and a non-cancerous HEK293 human cell line transfected with a plasmid encoding full-length PSMA. Differential centrifugation revealed that PSM' is localized predominantly to the cytosol of both these cell lines and is proteolytically active. Furthermore, the PSM' protein is N-glycosylated by a mixture of high-mannose and complex type oligosaccharides and therefore trafficked beyond the cis-Golgi compartment. CONCLUSIONS Our data suggest that the PSM' protein is likely not generated by alternative splicing of the PSMA gene but by different mechanism, probably via an endoproteolytic cleavage of the full-length PSMA.
Collapse
Affiliation(s)
- Petra Mlcochová
- Gilead Sciences and IOCB Research Centre, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | | | | | | | | |
Collapse
|
8
|
Sato Y, Suzuki Y, Ito E, Shimazaki S, Ishida M, Yamamoto T, Yamamoto H, Toda T, Suzuki M, Suzuki A, Endo T. Identification and characterization of an increased glycoprotein in aging: Age-associated translocation of cathepsin D. Mech Ageing Dev 2006; 127:771-8. [PMID: 16914181 DOI: 10.1016/j.mad.2006.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We found that 14 N-glycosylated proteins were accumulated in the rat cerebral cortex cytosolic fraction in the aging process by a comparative study with two-dimensional gel electrophoresis and concanavalin A staining. All proteins had high mannose and/or hybrid-type N-glycans, as indicated by the fact that they were sensitive to endoglycosidase H digestion. Three of these cytosolic glycoproteins were identified as cathepsin D, a lysosomal protease, by tryptic digestion and nano liquid chromatography electrospray ionization quadrupole time of flight mass spectrometry. The increase of cytosolic cathepsin D during aging was not due to lysosomal membrane disruption, as shown by the fact that the activities of beta-hexosaminidase and beta-glucuronidase, other lysosomal enzymes, did not increase in the cytosolic fraction. Although the total amount of cathepsin D increased during aging, the amount of cathepsin D in the microsomal fraction did not change, indicating a selective increase of cytosolic cathepsin D. This phenomenon was also observed in the hippocampus, cerebellum, kidney, liver, and spleen. Based on these results, we propose that cytosolic cathepsin D is a new biomarker of aging.
Collapse
Affiliation(s)
- Yuji Sato
- Research Team for Functional Genomics, Tokyo Metropolitan Institute of Gerontology, Foundation for Research on Aging and Promotion of Human Welfare, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Laughery MD, Todd ML, Kaplan JH. Mutational analysis of alpha-beta subunit interactions in the delivery of Na,K-ATPase heterodimers to the plasma membrane. J Biol Chem 2003; 278:34794-803. [PMID: 12826673 DOI: 10.1074/jbc.m302899200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The beta-subunit of the Na,K-ATPase is required to deliver functional alpha beta-heterodimers to the plasma membrane (PM) of baculovirus-infected insect cells. We have investigated the molecular determinants in the beta-subunit for the assembly and delivery processes. Trafficking of both subunits was analyzed by Western blots of fractionated membranes enriched in endoplasmic reticulum (ER), Golgi, and PM. Heterodimer assembly was evaluated by co-immunoprecipitation, and enzymatic activity was measured by ATPase assay. Elimination of enzymatic activity by D369A point mutation of the alpha-subunit had no effect on the compartmental distribution of the Na,K-ATPase, demonstrating that enzymatic functioning is not a prerequisite for PM delivery. Replacement of all three N-glycosylation site asparagines with glutamines produced no effect on the delivery to the PM or the activity of the enzyme, but increased susceptibility to degradation was observed. Analysis of beta-subunits in which the disulfide bonds were removed through substitution reveals that the bridges are important for PM targeting but not for assembly of the heterodimer. Assembly is supported by beta-subunits with greatly truncated extracellular domains. The presence of the amino-terminal domain and transmembrane segment is sufficient for assembly and PM delivery. Intermediate length truncated beta-subunits and some disulfide bridge substitution mutants assemble with the alpha-subunit but are not able to exit the ER. We conclude that there are different and separable requirements for the assembly of Na,K-ATPase heterodimer complexes, exit of the dimer from the ER, delivery to the PM, and catalytic activity of the dimer.
Collapse
Affiliation(s)
- Melissa D Laughery
- Department of Biochemistry and Molecular Biology, Oregon Health and Sciences University, Portland, Oregon 97239, USA
| | | | | |
Collapse
|
10
|
Sato Y, Naito Y, Grundke-Iqbal I, Iqbal K, Endo T. Analysis of N-glycans of pathological tau: possible occurrence of aberrant processing of tau in Alzheimer's disease. FEBS Lett 2001; 496:152-60. [PMID: 11356201 DOI: 10.1016/s0014-5793(01)02421-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In a previous study [Wang et al. (1996) Nat. Med. 2, 871-875], Wang et al. found (i) that abnormally hyperphosphorylated tau (AD P-tau) isolated from Alzheimer's disease (AD) brain as paired helical filaments (PHF)-tau and as cytosolic AD P-tau but not tau from normal brain were stained by lectins, and (ii) that on in vitro deglycosylation the PHF untwisted into sheets of thin straight filaments, suggesting that tau only in AD brains is glycosylated. To elucidate the primary structure of N-glycans, we comparatively analyzed the N-glycan structures obtained from PHF-tau and AD P-tau. More than half of N-glycans found in PHF-tau and AD P-tau were different. High mannose-type sugar chains and truncated N-glycans were found in both taus in addition to a small amount of sialylated bi- and triantennary sugar chains. More truncated glycans were richer in PHF-tau than AD P-tau. This enrichment of more truncated glycans in PHF might be involved in promoting the assembly and or stabilizing the pathological fibrils in AD.
Collapse
Affiliation(s)
- Y Sato
- Department of Glycobiology, Tokyo Metropolitan Institute of Gerontology, Japan
| | | | | | | | | |
Collapse
|
11
|
Anand R. Probing the topology of the glutamate receptor GluR1 subunit using epitope-Tag insertions. Biochem Biophys Res Commun 2000; 276:157-61. [PMID: 11006099 DOI: 10.1006/bbrc.2000.3457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
At least two different models for the transmembrane topology of the glutamate receptor subunits have been proposed. We investigated some features of these two models for the GluR1 subunit by inserting epitope tags between residues Lys(502)-Pro(503), Ala(632)-Glu(633), Lys(712)-Pro(713), or after the C-terminal residue Leu(889). The accessibility of the tags then was detected using a tag-specific antibody before and after detergent-permeabilizing oocytes expressing the tagged subunits. The epitope tag inserted between residues Lys(712)-Pro(713) is extracellular and after Leu(889) intracellular. Epitope tags inserted between residues Lys(502)-Pro(503) and residues Ala(632)-Glu(633) were not detectable. Collectively, these results provide supporting evidence for a previously proposed topological model of GluR subunits containing an N-terminal extracellular domain, three transmembrane domains, the first two of which are bridged by a reentrant membrane pore-lining loop, and an intracellular C-terminal domain.
Collapse
Affiliation(s)
- R Anand
- Neuroscience Center of Excellence, Department of Neurology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite D, New Orleans, Louisana 70112, USA.
| |
Collapse
|
12
|
Spura A, Riel RU, Freedman ND, Agrawal S, Seto C, Hawrot E. Biotinylation of substituted cysteines in the nicotinic acetylcholine receptor reveals distinct binding modes for alpha-bungarotoxin and erabutoxin a. J Biol Chem 2000; 275:22452-60. [PMID: 10791957 DOI: 10.1074/jbc.m001283200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although previous results indicate that alpha-subunit residues Trp(187), Val(188), Phe(189), Tyr(190), and Pro(194) of the mouse nicotinic acetylcholine receptor are solvent-accessible and are in a position to contribute to the alpha-bungarotoxin (alpha-Bgtx) binding site (Spura, A., Russin, T. S., Freedman, N. D., Grant, M., McLaughlin, J. T., and Hawrot, E. (1999) Biochemistry 38, 4912-4921), little is known about the accessibility of other residues within this region. By determining second-order rate constants for the reaction of cysteine mutants at alpha184-alpha197 with the thiol-specific biotin derivative (+)-biotinyl-3-maleimidopropionamidyl-3,6-dioxaoctanediamine , we now show that only very subtle differences in reactivity (approximately 10-fold) are detectable, arguing that the entire region is solvent-exposed. Importantly, biotinylation in the presence of saturating concentrations of the long neurotoxin alpha-Bgtx is significantly retarded for positions alphaW187C, alphaF189C, and reduced wild-type receptors (alphaCys(192) and alphaCys(193)), further emphasizing their major contribution to the alpha-Bgtx binding site. Interestingly, although biotinylation of position alphaV188C is not affected by the presence of alpha-Bgtx, erabutoxin a, which is a member of the short neurotoxin family, inhibits biotinylation at position alphaV188C, but not at alphaW187C or alphaF189C. Taken together, these results indicate that short and long neurotoxins establish interactions with distinct amino acids on the nicotinic acetylcholine receptor.
Collapse
Affiliation(s)
- A Spura
- Department of Molecular Pharmacology, Division of Biology and Medicine, Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | | | | | | | | | | |
Collapse
|
13
|
Clark RA, Küster B, Benallal M, Anner BM, Dwek RA, Harvey DJ, Wing DR. Characterisation of tissue-specific oligosaccharides from rat brain and kidney membrane preparations enriched in Na+,K+-ATPase. Glycoconj J 1999; 16:437-56. [PMID: 10737329 DOI: 10.1023/a:1007078511110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The organ-specific nature of the glycosylation of Na+,K+-ATPase-enriched preparations from kidney and brain tissues has earlier been indicated by the use of lectin-staining techniques. Na+,K+-ATPase is ubiquitous and abundant, and subject to upregulation during cell-division and in certain pathological conditions. Lectins specific for the different carbohydrates displayed by the Na+,K+-ATPases may, therefore, be useful carriers/mediators in tissue-specific targeting. N-linked oligosaccharides purified from Na+,K+-ATPase-enriched preparations from rat brain and kidney were consequently characterised in detail in this study using weak anion exchange and normal phase HPLC (combined with serial glycosidase digestions) and matrix-assisted laser desorption/ionisation mass spectrometry. The oligomannose series of glycans were most abundant in the brain tissue preparation and this contrasted with the renal-associated oligosaccharides that were dominated by families of tetra-antennary glycans (with/without a core fucose) with up to four lactosaminylglycan residues in either branched or linear formation.
Collapse
Affiliation(s)
- R A Clark
- Glycobiology Institute, Department of Biochemistry, University of Oxford, UK
| | | | | | | | | | | | | |
Collapse
|
14
|
Klaassen CH, Fransen JA, Swarts HG, De Pont JJ. Glycosylation is essential for biosynthesis of functional gastric H+,K+-ATPase in insect cells. Biochem J 1997; 321 ( Pt 2):419-24. [PMID: 9020875 PMCID: PMC1218085 DOI: 10.1042/bj3210419] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The role of N-linked glycosylation in the functional properties of gastric H+,K+-ATPase has been examined with tunicamycin and I-deoxymannojirimycin, inhibitors in glycoprotein biosynthesis and glycoprotein processing respectively. Tunicamycin completely abolished both K+-stimulated and 3-(cyanomethyl)-2-methyl-8-(phenylmethoxy)-imidazo[1,2a]pyridine (SCH 28080)-sensitive ATPase activity and SCH 28080-sensitive phosphorylation capacity. The expression level of both H+,K+-ATPase subunits remained unaffected. 1-Deoxymannojirimycin clearly affected the structure of the N-linked oligosaccharide moieties without affecting specific phosphorylation capacity. Purification of the functional recombinant enzyme from non-functional H+,K+-ATPase subunits coincided with purification of glycosylated beta-subunits and not of non-glycosylated beta-subunits. Transport of the H+,K+-ATPase beta-subunit to the plasma membrane but not its ability to assemble with the alpha-subunit dependent on N-glycosylation events. We conclude that the acquisition, but not the exact structure, of N-linked oligosaccharide moieties, is essential for biosynthesis of functional gastric H+,K+-ATPase in insect cells.
Collapse
Affiliation(s)
- C H Klaassen
- Department of Biochemistry, Faculty of Medicine, University of Nijmegen, The Netherlands
| | | | | | | |
Collapse
|
15
|
Abstract
Modification of Ser and Thr residues by attachment of O-linked N-acetylglucos-amine [Ser(Thr)-O-GlcNAcylation] to eukaryotic nuclear and cytosolic proteins is as dynamic and possibly as abundant as Ser(Thr) phosphorylation. Known O-GlcNAcylated proteins include cytoskeletal proteins and their regulatory proteins; viral proteins; nuclear-pore, heat-shock, tumor-suppressor, and nuclearoncogene proteins; RNA polymerase II catalytic subunit; and a multitude of transcription factors. Although functionally diverse, all of these proteins are also phosphoproteins. Most O-GlcNAcylated proteins form highly regulated multimeric associations that are dependent upon their posttranslational modifications. Evidence is mounting that O-GlcNAcylation is an important regulatory modification that may have a reciprocal relationship with O-phosphorylation and may modulate many biological processes in eukaryotes.
Collapse
Affiliation(s)
- G W Hart
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, School of Medicine 35294-0005, USA.
| |
Collapse
|
16
|
Arystarkhova E, Sweadner KJ. Isoform-specific monoclonal antibodies to Na,K-ATPase alpha subunits. Evidence for a tissue-specific post-translational modification of the alpha subunit. J Biol Chem 1996; 271:23407-17. [PMID: 8798546 DOI: 10.1074/jbc.271.38.23407] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Monoclonal antibodies to isoforms of the Na,K-ATPase have become important tools in the study of the enzyme's distribution, physiological roles, and gene regulation, and when their epitopes are defined, they are useful in the study of enzyme structure as well. Evidence is presented that the alpha3-specific antibody McBX3 recognizes an unusual epitope that is not present on alpha3 in the heart. The epitope, which is also found in kidney alpha1 from some species, was mapped to a site on the large intracellular loop near the ATP binding site. DNA sequencing of reverse transcribed-PCR products encompassing the corresponding regions from alpha3 from brain (where McBX3 recognizes alpha3) and heart demonstrated that the tissue difference in epitope is not due to alternative splicing of the mRNA. Instead, hydroxylamine sensitivity indicated that the antibody recognizes a post-translational modification. The epitope for a new antibody for alpha3, XVIF9-G10, was mapped to a site near the N terminus, a location analogous to the sites for the well-characterized antibodies McK1 (alpha1) and McB2 (alpha2). The antibody XVIF9-G10 reacted with the alpha3 of the heart as well as that of the brain; however, McBX3 and XVIF9-G10 both stained the same cellular structures in sections of the rat retina. A new alpha1-specific antibody, 6F, was characterized and mapped to another site near the N terminus; this antibody has broader species specificity than the other well-characterized alpha1 antibody, McK1.
Collapse
Affiliation(s)
- E Arystarkhova
- Laboratory of Membrane Biology, Neuroscience Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | | |
Collapse
|
17
|
Pedemonte CH. Inhibition of Na(+)-pump expression by impairment of protein glycosylation is independent of the reduced sodium entry into the cell. J Membr Biol 1995; 147:223-31. [PMID: 8558588 DOI: 10.1007/bf00234520] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Previous studies indicate that inhibition of protein N-glycosylation reduces Na(+)-pump activity. Since this effect is preceded by an inhibition of the entry of sodium into the cell, it is unclear whether the reduced Na(+)-pump is produced by the inactivation of protein glycosylation per se or by the lower intracellular sodium concentration. We compared the effects of tunicamycin, which inhibits protein glycosylation, and amiloride, which inhibits the entry of sodium into the cell, on the expression of the Na(+)-pump activity in A6 cells. The short-circuit current across A6 epithelia, which corresponds to sodium ions transported through the Na+ channel and the Na(+)-pump, was almost totally inhibited after 24-hr treatment with 1 microgram/ml tunicamycin. The maximal Na(+)-pump activity, measured after permeabilizing the apical cell membrane with amphotericin B, was only 30% inhibited. This inhibition increased to 80% after 72-hr treatment with tunicamycin. Thus, tunicamycin inhibits the activities of both the apical Na+ channel and the basolateral Na(+)-pump. However, the reduced number of Na(+)-pump molecules, as well as the inhibition of the Na(+)-pump activity, were not observed when the Na+ channel was inhibited for 72-hr with amiloride. Thus, the reduced Na(+)-pump expression produced by inactivation of protein glycosylation is not secondary to reduced entry of sodium into the cell.
Collapse
Affiliation(s)
- C H Pedemonte
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX 77204-5515, USA
| |
Collapse
|
18
|
Suzuki T, Kitajima K, Inoue S, Inoue Y. N-glycosylation/deglycosylation as a mechanism for the post-translational modification/remodification of proteins. Glycoconj J 1995; 12:183-93. [PMID: 7496130 DOI: 10.1007/bf00731318] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- T Suzuki
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan
| | | | | | | |
Collapse
|
19
|
Benallal M, Anner BM. Major organ-specific glycoproteins in isolated brain and kidney membranes identified as Na,K-ATPase subunits by combined glycan-, lectin-, and immunoblotting. Biosci Rep 1995; 15:21-36. [PMID: 7647289 DOI: 10.1007/bf01200212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In the present work combined glycan-, lectin-, and immunoblotting of isolated brain and kidney membranes shows that the alpha and beta subunits of Na,K-ATPase are the most abundant glycoproteins. Further, Datura stramonium and Galanthus nivalis agglutinins recognize the Na,K-ATPase subunits in a mutually exclusive manner in membranes from human, rabbit and rat brain or human, rabbit, rat, pig and dog kidney indicating the presence of species-independent organ-typical glycoforms. The glycosylation status is not related to the ouabain-sensitivity. Taken together, the data reveals organ-specific glycoforms of Na,K-ATPase which might have roles for organ identification and recognition.
Collapse
Affiliation(s)
- M Benallal
- Laboratory of Experimental Cell Therapeutics, Geneva University Medical School, Switzerland
| | | |
Collapse
|
20
|
Rakowska M, Zborowski J, Corazzi L. A fusogenic protein from rat brain microsomal membranes: partial purification and reconstitution into liposomes. J Membr Biol 1994; 142:35-42. [PMID: 7707352 DOI: 10.1007/bf00233381] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The procedures for purification and reconstitution of rat brain microsomal membrane protein that causes fusion of liposomes at acidic pH are described. A 1,860-fold purification was achieved, starting from the detergent-solubilized microsomal membranes. The fusion process was assayed spectrofluorimetrically by monitoring the formation of terbium-dipicolinic acid complex (Wilschut, J. et al. 1980. Biochemistry 19:6011-6021) evoked by the protein after mixing of two populations of liposomes. The fusogenic activity of the protein inserted into the membrane of Tb3+-containing vesicles was found to be strongly dependent on phospholipid composition and was higher in vesicles enriched with exogenous phosphatidylserine, phosphatidylglycerol and phosphatidylethanolamine than in those prepared with an excess of phosphatidylcholine. The vesicles enriched in negatively charged phospholipids were bound to Concanavalin A coupled to Sepharose-4B and could be released from this column only in the presence of a high concentration of alpha-methylmannopyranoside and detergent, indicating a glycoprotein nature of the fusogenic protein. Furthermore, these data show that protein inserted into membrane has its oligosaccharide chains exposed to the environment.
Collapse
Affiliation(s)
- M Rakowska
- Institute of Biochemistry and Medical Chemistry, University of Perugia, Italy
| | | | | |
Collapse
|
21
|
Benallal M, Anner BM. Identification of organ-specific glycosylation of a membrane protein in two tissues using lectins. EXPERIENTIA 1994; 50:664-8. [PMID: 8033974 DOI: 10.1007/bf01952869] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Since glycosylation of proteins is performed by the host cell, and variable sugar groupings can confer heterogeneity on the same polypeptide, we wished to see whether membrane proteins, in particular the ubiquitous transmembrane Na,K-ATPase, could be glycosylated differently in different organs. Using a highly sensitive enzyme-linked antibody detection system of bound digoxigenin-labelled lectins on nitrocellulose sheets containing electroblotted alpha and beta subunits of kidney and brain Na,K-ATPase, isolated from various rat strains, in combination with isoform-specific immunoblots, we discovered that brain Na,K-ATPase was highly mannosylated in contrast to renal Na,K-ATPase. Thus, we describe the existence of organ-related glycoforms of an integral ubiquitous membrane protein, i.e. diversification of the same polypeptide by organ-typical sugars. At the same time, the presence of the same glycosylation pattern can make distinct protein isoforms occurring in a same organ more homogeneous. Such organ-related glycoforms may serve for tissue identification and as tissue-specific receptors.
Collapse
Affiliation(s)
- M Benallal
- Laboratory of Experimental Cell Therapeutics, Geneva University Medical School, Switzerland
| | | |
Collapse
|
22
|
Santacruz-Toloza L, Huang Y, John SA, Papazian DM. Glycosylation of shaker potassium channel protein in insect cell culture and in Xenopus oocytes. Biochemistry 1994; 33:5607-13. [PMID: 8180185 DOI: 10.1021/bi00184a033] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have studied the glycosylation of Shaker K+ channel protein made in two expression systems: an insect cell culture line and amphibian oocytes. In both systems, two potential sites for N-linked glycosylation were modified. The modified sites were located between the first and second putative transmembrane segments, S1 and S2. Although the same sites appeared to be glycosylated in both systems, the fraction of protein glycosylated and the size, structure, or composition of the oligosaccharide chains added were quite different. The results indicate that the S1-S2 loop is extracellular, consistent with a cytoplasmic location for the N-terminus and a transmembrane disposition for hydrophobic segment S1. We have also shown that glycosylation occurs in two stages in oocytes, generating an immature and a mature form of Shaker protein. However, glycosylation is not required either for the assembly of functional channels or for their transport to the cell surface.
Collapse
Affiliation(s)
- L Santacruz-Toloza
- Department of Physiology, School of Medicine, University of California, Los Angeles 90024-1751
| | | | | | | |
Collapse
|
23
|
Mather IH, Jack LJ. A review of the molecular and cellular biology of butyrophilin, the major protein of bovine milk fat globule membrane. J Dairy Sci 1993; 76:3832-50. [PMID: 8132890 DOI: 10.3168/jds.s0022-0302(93)77726-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The molecular and cellular biology of the milk protein butyrophilin is reviewed. Butyrophilin constitutes more than 40% by weight of the total protein associated with the fat globule membrane of bovine milk. Closely related proteins are abundant in the fat globule membranes of many other species. Butyrophilin is synthesized as a peptide of 526 amino acids with an amino-terminal hydrophobic signal sequence of 26 amino acids, which is cleaved before secretion in association with the fat globule membrane. Hydropathy analysis and in vitro translation of butyrophilin mRNA indicate that the protein associates with membranes in a type I orientation via a single stretch of 27 hydrophobic amino acids in the approximate middle of the sequence. Evidence that butyrophilin is incorporated into fat globule membrane as a transmembrane protein and as a cytoplasmically oriented peripheral component is discussed. The carboxy-terminal sequence of butyrophilin is significantly homologous to two other proteins: ret finger protein and the 52-kDa nuclear antigen A of Sjögren's syndrome. Expression of bovine butyrophilin mRNA correlates with the onset of milk fat secretion toward the end of pregnancy and is maintained throughout lactation. The possible function of butyrophilin in the secretion of milk lipid droplets is discussed.
Collapse
Affiliation(s)
- I H Mather
- Department of Animal Sciences, University of Maryland, College Park 20742
| | | |
Collapse
|
24
|
Haworth RS, Fröhlich O, Fliegel L. Multiple carbohydrate moieties on the Na+/H+ exchanger. Biochem J 1993; 289 ( Pt 3):637-40. [PMID: 8382044 PMCID: PMC1132222 DOI: 10.1042/bj2890637] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Affinity-purified antibodies against the C-terminal region of the Na+/H+ exchanger (NHE-1) were used to analyse the carbohydrate moiety of the protein. The Na+/H+ exchanger in human placental brush-border membranes has an apparent molecular mass of 105 kDa. Incubation of intact or detergent-solubilized membranes with glycopeptidase F removed the carbohydrate moiety and increased the apparent mobility of the exchanger. Digestion with endoglycosidase-F caused a similar change in mobility, but endoglycosidase-H had no effect, suggesting that the placental Na+/H+ exchanger is a glycoprotein of the biantennary complex type. Removal of the carbohydrate moiety with glycopeptidase F had no effect on the ability of the protein to promote the exchange of Na+ for H+, and had no detectable effect on the sensitivity of the exchanger to trypsin. Limited digestion with glycopeptidase F and neuraminidase indicated the presence of two intermediate forms between the fully glycosylated and the deglycosylated protein. This suggests the presence of at least two, and possibly three, N-linked carbohydrate moieties.
Collapse
Affiliation(s)
- R S Haworth
- Department of Pediatrics, University of Alberta, Edmonton, Canada
| | | | | |
Collapse
|
25
|
Chapter 2 Structure and function of gastric H,K-ATPase. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/s0167-7306(08)60064-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
26
|
Van Uem TJ, Swarts HG, De Pont JJ. Determination of the epitope for the inhibitory monoclonal antibody 5-B6 on the catalytic subunit of gastric Mg(2+)-dependent H(+)-transporting and K(+)-stimulated ATPase. Biochem J 1991; 280 ( Pt 1):243-8. [PMID: 1720615 PMCID: PMC1130626 DOI: 10.1042/bj2800243] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The monoclonal antibody 5-B6, directed against the alpha-subunit of pig gastric H+,K(+)-ATPase (Mg(2+)-dependent H(+)-transporting and K(+)-stimulated ATPase), was shown to be a potent inhibitor of the K(+)-ATPase activity, thereby binding to the cytoplasmic side of the alpha-subunit of the enzyme [Van Uem, Peters & De Pont (1990) Biochim. Biophys. Acta 1023, 56-62]. In order to define the epitope for 5-B6 on pig gastric H+,K(+)-ATPase more precisely, the alpha-subunit of the enzyme was subjected to limited proteolysis followed by chemical cleavage. Restricted proteolysis with papain followed by sequence analysis yielded an immunoreactive fragment of 27 kDa beginning at Ser379. This fragment was water-soluble and possessed the fluorescein isothiocyanate-reaction site. Limited tryptic digestion in the presence of K+ gave rise to an immunoreactive 56 kDa fragment beginning at Ile456, thus restricting the location of the epitope from Ile456 to the C-terminal end of the 27 kDa fragment (around residue 620). Further degradation of the 27 kDa fragment by means of formic acid cleavage at Asp-Pro bonds resulted initially in the formation of two non-immunoreactive fragments of 17 kDa and 11 kDa, indicating that the epitope for 5-B6 has to be localized around the chemical cleavage sites Asp507 and/or Asp510. Comparison of the primary structure of the alpha-subunits of gastric H+,K(+)-ATPase and non-immunoreactive rat kidney Na+,K(+)-ATPase shows almost no similarity for the sequence containing these formic acid cleavage sites (Thr504-Leu-Glu-Asp-Pro-Arg-Asp-Pro-Arg512), whereas the adjacent sequences are nearly 100% identical. These findings strongly suggest that the epitope for 5-B6 includes (part of) this sequence.
Collapse
Affiliation(s)
- T J Van Uem
- Department of Biochemistry, University of Nijmegen, The Netherlands
| | | | | |
Collapse
|